This invention relates to material handling, and particularly, to a machine and method for moving valve type bags from a conveyor into position with respect to a bag filling machine.
Valve type bags are typically made from paper and are folded to form an end flap having an opening at one end. Valve bags are used to contain numerous types of dry particulate materials such as cement, sand and edible products. The valve bag is filled by inserting the bag opening onto a material dispensing nozzle of a bag filling machine. Dry material is discharged through the nozzle filling the bag and is thereafter removed from the bag filling machine. Material within the bag remains within the valve bag since its presence within the bag exerts a closing force on the valve bag opening. Valve type bags are normally shipped in a folded and stacked condition. In certain instances, the bonding compounds used to fabricate the bag can prevent the end flap of the bag, which contains the valve opening, from being readily folded and opened. Therefore, to insure reliability, a valve bag placing machine must ensure that any bond between the bag end flap and the bag side is broken. Since valve bag placing machines are typically used in mass production commercial settings, it is further desirable that such machines be capable of high production rates, are reliable and which are low in cost and simple in construction. It is another desirable feature to enable such machines to be automatically controlled.
The above desirable features of a valve placing machine and method are provided in accordance with this invention. The valve placing machine includes a valve bag clamping assembly which is attached at the end of an arm which is rotatably and linearly movable by an actuator assembly. The valve bag clamping assembly includes vacuum cups which attach to the valve bag end. Additional vacuum cups attach to the bag side. Once attached, both these sets of vacuum cups are raised and a valve opening rod contacts the midsection of the valve bag between the points of contact of these vacuum cups to the bag. This contact by the valve opening rod effectively causes the bag end flap to be stripped away from the side of the bag. Thereafter, one of the vacuum cups is released and the valve bag clamping assembly is caused to rotate by the actuator assembly. After one of the vacuum cups is released, the valve bag clamping assembly, through articulated arms, causes bag engaging means to contact the bag side and pull open the valve opening. Thereafter, the carriage assembly moves the bag linearly such that the valve opening is placed around a material dispensing nozzle of the bag filling machine. The valve bag placing machine according to this invention is preferably automatically operated by an air logic system.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings.